Re: Freescale Linux BSP review

[Jerome Glisse <j.glisse@gmail.com>]

On Mon, Dec 13, 2010 at 10:18 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Monday 13 December 2010, Jammy Zhou wrote:
>> On Mon, Dec 13, 2010 at 4:45 AM, Linus Walleij <linus.walleij@linaro.org>wrote:
>>
>> > On 11 December 2010 22:41, Arnd Bergmann <arnd@arndb.de> wrote:
>> >
>> > * amd-gpu -- a single but huge driver for the GPU. As is normally the
>> >>             case with GPU drivers, we can expect long discussions
>> >>             before it will get considered for mainline
>> >>  4 patches
>> >>  98 files changed, 278321 insertions(+), 0 deletions(-)
>> >>
>> >
>> > Just out of curiosity, following the discussion between Dave Airlie
>> > and Codeaurora this summer re GPU driver shims.
>> >
>> > Is the AMD GPU exposing all functionality in its kernel driver or
>> > is there some userspace blob somewhere with lots of e.g. GL
>> > goodies?
>> >
>> All the functionality for the kernel driver of AMD GPU Z430/Z160 (now
>> belongs to Qualcom) is exposed. But we need accompanied userspace library to
>> call these functionality (buffer management, command submission, ...).
>
> Who owns these components? If it's closed source, the only options we
> have are lobbying for complete release of the specs for a reimplementation
> or reverse-engineering the drivers, which may at least get easier with
> a user space driver than it would be with a kernel driver.
>
> Until there is a solution with an open source user space part, I would
> suggest that the driver better be dropped from the Freescale BSP and
> we should at least not waste time reviewing it.
>
>        Arnd

>From a quick look it also seems that the API exposed to userspace
would allow easy abuse of the GPU to access any system ram. There is a
reason we do expensive command checking in the other amd gpu driver
(drivers/gpu/drm/radeon/*cs.c files)

Cheers,
Jerome